The living polymerization of olefins is a method utilized to control molecular weight and final product properties in polymers. The polymerizations are called living because the initiators grow only one chain per initiator molecule and the polymerization continues until monomer is exhausted rather than terminating when the chain reaches a certain length or the catalyst is exhausted Para-methylstyrene (pMeSt) has reportedly been polymerized in a living fashion by the organic esters/BC13 initiating system (R. Faust and J. P. Kennedy; Polymer Bulletin, 19, 29 (1988)). Living polymerization of para-methylstyrene is also claimed with a 2,4,4-trimethylpentychloride/titanium tetrachloride (TMPCl/TiCl4) initiating system in the presence of triethylamine (Et.sub.3 N) although initiation is reportedly slow. Likewise, living polymerization has also been reportedly used to synthesize block copolymers. Y. Tsunogae and J. P. Kennedy reported the synthesis of para-methylstyrene--polyisobutylene--paramethylstyrene triblock copolymer with dicumylchloride/titanium tetrachloride/triethylamine/(DiCumCl/TiCl.sub.4 /Et.sub.3 N) in 40 parts by volume methylene chloride and 60 parts by volume n-hexane (MeCl/n-hexane) at -80 degrees C. system (Y. Tsunogae and J. P. Kennedy; Polymer Bulletin, 27, 631(1992)). The triblocks manifested low tensile strength (14.1 MPa) indicating poor blocking efficiency.
Recently is has been discovered that living homopolymerization of isobutylene or styrene and sequential block copolymerization of said monomers can be achieved by an organic ester, ether or chloride/TiCl.sub.4 or BC13 initiating systems in the presence of a proton trap di-tert-butyl pyridine (DTBP) leading to block copolymers with high efficiency (R. Faust, M. Gyor, H. C. Wang, "Living Carbocationic Process", U.S. patent application Ser. No. 07/730,363 filed Jul. 15, 1991). The above procedure has produced low blocking efficiency with para-methylstyrene.